Sound-reproducer.



l. 1. CMEH.

SOUND REPRDDUCEH. APPLscATloN man JULY 24.1914.

` Mr/955555 l ATTORNEY JOHN J. COMER, OF CHICAGO, XLLINOIS, ASS'JGNQR TG UTOMATIC ENUNCATOR CGM PANY, OF CEICGO, ILLINOIS, A CORJORATION OF IllLLNGIS.

SOUND-nEPnODUcEB..

To all w hom it mul concern: Y!

Be it known that I, Jenn J. Corien, a citil zen of the United States ofv America, and

resident of Chicago, Cook county, Illinois? have invented a certain new and useful Iniproveinent in Sound-Reproducers, of which .adapted tor use in connection with telephonic or loud spenlriiin' circuits. Moreparticularly the objectol" my invention is t produeefan instrument oi' the above eliaraeter which is easily and effectively adjusted, as for example, by short cirouiting vthe inagnetic circuit ot the controllingr magnet.

An'iong the objects of my invention are:

, To provide a cheaper and more simple and also more eiiicient instrument of the above character than heretofore.V To provide in such an instrument a more delicate and eilicient means of adjustment.

it is also an object to provide certain details of improvement for the purpose of increasing the etiiiciency and serviceability of an instrument of the above character.

rilie means for acconiplisliingthe foregoing` and other useful ends are hereinafter set forth and claimed. i

Referring 'to the accompanying drawing Figure l shows a sectional elevation ot the 'instrument through the middle along a plane at right angles to the limbs of' the magnet. Fig. 2 is a detail top View showing the knife edge of the vibrating armature. Fig. 3 a curve showing the relation of Jtort-es.

Said magnet has two steel limbs 2 and 3, 'the latter extending below the former yand provided at Lits lower extension with an open--v ing Afor securing the instrument, as for example by a bolt e, to anything suitable, as to the holder 5 for example. These two limbs are bolted together near the lower end by a bolt 6, clamping between the limbs a piece of soft iron 7 of suitable thickness to keep them 'apart a proper distance. Near L their upper'end ,they are bolted together by a' brass bolt 8, clamping' between the limbs a brass piece 9 and a sof iron pole piece 10. This bolt, furthermore, clamps to the outer side of the member 2 a brass support l1 and v,to the outside. of the othermember 3 a brass -1 support 12. On the upper end ofthe pole piece 1G there is a magnetic coll 13 through the mediiim of. w ich Vthe armature 14 is op- Specicatoii of Letters atent.

the limbs of the magnet'.

Patented June 14.9, 193.2.

ppiipation inea .my 2t, 1914.. senti so. smsen.

erated. This armature has one end resting up against an angle heel'piece 1.5 which is secured tothe member 1l in any suitable manner as for example, by a screw. The other end of the armature which is elon gated passes through a holejin-the lower end oi' the link 16 where the twovare held.

together in a iiexible jointl by eollodion4 The other end .of the link i6 is secured .to the diaphragm 17l in any suitable manner.l riChe diaphragm ,is mounted on the brass cup 18 between the insulating rings 19'of suitable soft material as for example, rubber, to

' keep it from metallic contact with the blip.

This cup is secured to the brass supports 11 and 1 2 by suitable screws. The cup is provided with a cap 2O which is 'secured to the i cup as for example by screws. This cap 'has a threaded orifice into which the tube 2l.-is screwed as shown7 said tubeforming an chit -for the sound produced by the diaphragm 17. AThe whole instrument is incased by a tube 22 which is supported by the heads 23 and 24 as shown.

the soft iron piece that is clamped between The cap 23 is screwed to the tube 21. It will be underf stood that a permanent magnet in this in`- stiuinent acts upon the armature 13 to draw it toward the pole piece l0 with considerable force. diaphragm l? and the end which rests on the limb 2 is only held there by magnetic force. except the heel piece 1,510 hold it in position. `When the instrument is put together the connection between the armature 14 and diaphragm 17 is adjusted so that the diaphragm takes all the pull and holds the armature lifted from' the pole piece 10 a suitable dis? tance. N ow, after the instrument is closed and connected up and put in use it sometimes becomes desirable to vary the adjustnient of the armature 1i. Ordinarily it is necessary to disconnect the instrument for doing this. Sometimes however, a series of links and levers areproyided which enable the adjustment to be made without taking the instrument to pieces but it involves the mechanical meddling with the connection between the diaphragm and the armature which is detrimental to the instrument. Furthermore, in such cases the levers sup`- plied to reduce the pull'of thc armature neo essarily prevent the instrument from being The head 23 is held inv place by screws 25 which are embedded There are no screws or other devices' This armature in turn pulls on the adjustment may be carried on 'to vary it as and also the human voice described so as to adapt' it for sounds of great volume or sound of less volume. By moving the screw back and forth the armature 14 may be made to recede from or draw nearer to the bolt piece. l/Vith this instrument I have 4found it possible to reproduce properly the notes of a piano for example so that differences in quality are readily detected. Notwith standing that the instrument ,is so accurate it is made with less parts and in a simpler manner than any similar instrument heretofore. The particular arrangement of the parts of the magnet and of the casing contribute not only toward making the instrument, more compact and'simple but contribute also to its eliciency. As shown in the drawings the electroinagnet which hasas its core the pole piece 10 is electrically connected with any suitable circuit which may contain a microphone and a battery for energizing the electromagnet and 'for varying the energizing current in its circuit.

The particular arrangement which is above described therefore, shows the provision of an armature which. is designed to operate while under the action of two opposing forces. One of these opposing forces is the tension which is produced by the diaphragin assisted by the reinforcing cushion upon which the diaphragm rests. The other opposing force is the magnetic field of the magnet which also acts upon the armature 14. These two opposing forces are balanced through the medium of the lever arrangement which is provided between the magnet and the diaphragm. This lever has one fulcrum resting upon limb 2 of the magnet and uses the magnetic field as a power' and the opposing tension as a weightl By this arrangement the opposing forces are so bal-l anced after adjustment that if the armature Y14 is moved by external means either toward or away from lthe pole piece this movement causes, of course, a variation in the magnetic pull on the armature and it causes a corresponding variation in the tension opposing the same so that the fufinature remains just where it is left. For example if we take a toothpick and move the armature away from the pole piece it remains. If we bring it toward the pole piece it remains.

pull so that the at one end a soft iron This is the first time that this result has ever'been obtained in an instrument of this character. Referring to Fig. 3, M repre-V sents the magnetic pull on the armature and T the tensioi The curve V shows the relation of these forces. It is obvious that this armature may be moved by an external force applied for example through the Inedium of a tooth-pick to any point located on the curve between the points .P and Q. and that it will remain balanced there. But if takenbeyond the limit indicated by the points I and Q the balance will be -disturbed. Also it will be seen that this balance may be disturbed by energizing the 80 electromagnet 13 to increase the magnetic armature will stay where. put by the tooth-pick, thus impairing the efiiciency of the instrument. Therefore, I prefer to use in connection with this instru'- ment alternating currents for vibrating the diaphragm as indicated in the circuit Fig. 1. Of course, it will be understood that the magnetic pull may be produced by an electromagnet instead-of by a permanent magnet as described in this case and then balance the instrument to permit it t respond to the sound undulations which may be su. perimposed upon-the magnetizing current, but with such an arrangement thev balance will be disturbed each time that the energizing circuit is broken-when the instrument is disconnected. In either case however, the principle is the same. As has been stated sav the point at which the armature engages W the link that is fastened to the diaphragm is connected with collodion. This collodion forms a flexible joint of sufficient consistency to hold the armature inl position and at the same time prevent any undesirable nolvement between the armature `and the 1n r. f

l/Vhat I claim is:

l. In an electrical re reducer awpermanent magnet having twoglimbs bolted in parallel, one of which limbs sets higher than the other, and also one of said limbs having pole piece .extending Hush with one end of the1 higher limb and an electromagnet located thereon., the` other end of said limb being perforated for mounting the instrument, a diaphragm mounted upon supports resting upon both said magnet members, and an armature for said magnet one end resting on the higher limb and the other end supported by the diaphragm directly said instrument inclosed in a case, the lower limb being located within, and coinciding with thelongitudinal axis of the casing but with the perforated end projecting through the end of the casing, the' higher limb of said magnet being wholly contained Within said casing.

2. In an electrical reprodueer a perma- Y nent magnet having tWo members bolted in parallel, one of which members sets higher than the other, and also one of said limbs members, said magnet iiiclosed in a ca'sethe lower magnet being located With its longitudinal axis coinciding with the longirtudinal axis of the casing but With the perforated end projecting over the end of the casing, the higher limb of Said magnet beingv `Wholly contained Within said casing, and a magnetic shunt for deflecting the magnetic eld from the armature.

3. In an electrical reproducer a magnet, an armature, a magnetic field acting upon said armature a tension producing means acting upon said armature in opposition! to Said field, a diaphragm controlled by said armature through the medium ot' a link and a joint, said joint cemented together by nonmetallic flexible material to avoid rattling. 4. In an electrical reproducer a magnet, an armature,- a magnetic field acting upon said armature a tension producing means acting upon said armature in opposition to said eld, a diaphragm controlled 'by said armature through the medium of a link and a joint, Said' joint cemented by non-metallic flexible material -to aijoid rattling., and a magnetic shunt` for Varying the magnetic pull of the armature on the diaphragm.

Signed by me at Chicago, Illinois, this- 16th day of July, 1914.

Witnesses:

GEORGE A. YANooHoWSKI, CHAs. M. CANDY.

.ici-1N J. COMER. l 

